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#include <iostream>
#include <functional>
// Universal allocator
namespace memory
{
void* ptr{};
}
void* operator new([[maybe_unused]]std::size_t n) // throw(std::bad_alloc) - don't throw
{
std::cout << "new\n";
// Just return the supplied stack pointer
return memory::ptr;
}
void operator delete(void*) throw()
{
std::cout << "delete\n";
// Do nothing. actual memory is allocated on the stack
}
void operator delete(void*, std::size_t) throw()
{
std::cout << "delete[]\n";
// Do nothing. actual memory is allocated on the stack
}
//void foo() __attribute__((noinline))
int main()
{
char buf[256];
memory::ptr = buf;
std::cout << " ** strings:\n";
{ // strings
// now this is ok:
std::string str(32, 'a');
std::cout << str << '\n';
std::string str2(24, 'b');
std::cout << str << '\n'; // the contents of str has been overwritten
// this will also allocate, but supply the same buffer - ok
str = "hello world hello world hello world";
// this is also ok, but due to SSO
std::string sso{"hello"};
}
std::cout << " ** lambdas:\n";
{ // lambdas
std::function<int()> f;
{
char foo[16]{};
f = [=]()__attribute__((noinline)) // capture up 16 bytes - ok
{
int i = 0;
for(auto v : foo)
{
i += v;
}
return i;
}; // capture foo by copy - inlined
}
[[maybe_unused]]auto x = f();
}
}
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